Surgical devices having a gel component have been previously described. Examples include gel rollers in trocar seal housings, gel-containing caps in hand access devices and various other types of devices used in surgical and/or medical procedures. Examples of such devices are described in U.S. patent application Ser. No. 10/913,565, filed Aug. 5, 2004, U.S. patent application Ser. No. 10/776,387, filed Feb. 10, 2004, and U.S. patent application Ser. No. 10/381,220, filed Mar. 20, 2003; see also, U.S. Provisional Patent Application No. 60/241,958, filed Oct. 19, 2000, U.S. Provisional Patent Application No. 60/492,949, filed Aug. 6, 2003, and U.S. Provisional Patent Application No. 60/312,683, filed Aug. 14, 2001, the entire disclosures of which are hereby incorporated by reference as if set full herein.
Typically, the gel material performs a sealing function, conforming around the exterior of medical instruments inserted into a patient's body cavity through the gel (in the case of hand access devices, for example) or between gel rollers (in the case of trocar seals, for example) to prevent escape of insufflation gases or body fluids. Thus, it is important that the gel material be compliant enough to permit passage of medical instruments (or the surgeon's hand, in the case of hand access devices), but also resist compression and tearing.
One example of a gel material, suitable for use in some surgical devices, is a KP-12 copolymer gel, where the copolymer component of the gel comprises an SEBS (styrene ethylene butylene styrene) copolymer. The KP-12 gel material comprises a mixture of a KRATON® SEBS copolymer, PENRECO® DRAKEOL® mineral oil, a colorant, and an antioxidant. Such examples are described in U.S. patent application Ser. No. 10/776,387, filed Feb. 10, 2004 and U.S. patent application Ser. No. 10/913,565, filed Aug. 5, 2004, and U.S. Provisional Patent Application No. 60/492,949, filed Aug. 6, 2003 and U.S. Provisional Patent Application No. 60/312,683, filed Aug. 14, 2001, the entire disclosures of which are hereby incorporated by reference as if set in full herein.
Ideally, gels used in surgical devices have low durometer, high tear strength, high elongation, high compliance, and a resistance to tearing. While previously described gels, such as KP-12, meet some of these requirements, they also tend to exhibit a high degree a tack. Tackiness is particularly a problem in the case of gel rollers in trocar seals. The gel trocar seal in one aspect uses rotational movement of two opposed gel rollers such that the gel rollers contact each other and freely roll in response to inserted instrumentation. The gel rollers also roll relative to the trocar housing. A high degree of tackiness may inhibit the rotational movement of the rollers.
In hand access devices, high tackiness may inhibit passage of instruments or the surgeon's hand through the device, requiring the use of lubricants such as petrolatum on the gloved hand or instrument. A hand-access device pre-coated with a lubricant such as oil or petrolatum is messy and difficult to handle, and requiring the surgeon to apply a lubricant either onto his or her gloved hand, the access device and/or the medical instruments to be inserted therethrough requires additional time and additional materials in the operating room.
What is needed, therefore, are composite gel materials that exhibit low durometer, high tear strength, high elongation, high compliance, resistance to compression, and a non-tack surface. Alternatively, what is needed are coatings for gel materials that are quickly and easily activated to reduce tack and/or increase lubricity of the gel materials and to reduce frictional forces between mating gel material components and/or between gel material components and/or non-gel material components.